Method and system to detect tampering using light detector

• US 7,436,316 B2
• Filed: 01/05/2006
• Issued: 10/14/2008
• Est. Priority Date: 01/05/2006
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Tucker, James L., Fleischman, Scott G.
• Primary Examiner(s): Bugg; George A
• Assistant Examiner(s): Lau; Hoi C
• Application Number:
  US11/325,733
• Publication Number:
  US 20070152840A1
• Time in Patent Office: 1,013 Days
• Field of Search: 340555-557, 340/686.1, 340/686.4, 340/815.42, 340569-570, 250221-224
• US Class Current: 340/686.1
• CPC Class Codes: G06F 21/86 Secure or tamper-resistant housings
• CPC Class Codes: G08B 13/186 using light guides, e.g. optical fibres

Abstract

An optical anti-tamper system including a light emitting layer located within a chassis, a light detecting layer located within the chassis and one or more detectors optically coupled to the light detecting layer. The one or more detectors are in communication with an alarm. The alarm is operable to transmit a tamper-event warning signal if an increased light level is detected by at least one detector.

Claims

1. An optical anti-tamper system, the system comprising:

a light emitting layer located within a chassis comprising one or more emitter optical fibers, each emitter optical fiber including a plurality of output ports on a side surface of the emitter optical fiber, the output ports operable to transmit light propagating through the emitter optical fiber outside of the emitter optical fiber;

a light detecting layer located within the chassis comprising one or more detector optical fibers, each detector optical fiber including a plurality of input ports on a side surface of the detector optical fiber, the input ports operable to receive light for propagation within the detector optical fiber; and

one or more detectors optically coupled to the light detecting layer, the one or more detectors in communication with an alarm, wherein the alarm is operable to transmit a tamper-event warning signal if an increased light level is detected by at least one detector.

2. The system of claim 1, the system further comprising:

one or more light sources optically coupled to the light emitting layer.

3. The system of claim 1, the system further comprising:

a transparent layer located at an interface between the light emitting layer and the light detecting layer.

4. The system of claim 3, wherein the transparent layer is a transparent abrasive layer comprising a gel and abrasive particles dispersed within the gel.

5. The system of claim 1, wherein one or more light sources are optically coupled to an input end of the one or more emitter optical fibers, wherein the output ports on a side surface of the emitter optical fiber are bevel cuts to at least a core of the emitter optical fibers.

6. The system of claim 5, wherein a thin film opaque layer covers the bevel cuts to at least a core of the emitter optical fibers.

7. The system of claim 6, wherein the input ports on a side surface of the detector optical fiber are bevel cuts to at least a core of the detector optical fibers.

8. The system of claim 1, the system further comprising:

a transparent layer; and

an opaque layer in contact with the transparent abrasive layer, wherein the input ports on a side surface of the detector optical fibers are bevel cuts to at least a core of the detector optical fibers, wherein the output ports on a side surface of the emitter optical fibers are bevel cuts to at least a core of the emitter optical fibers, and wherein the opaque layer is interleaved between adjacent emitter optical fibers and detector optical fibers.

9. The system of claim 8, wherein the transparent layer is a transparent abrasive layer comprising a gel and abrasive particles dispersed within the gel.

10. The system of claim 1, wherein the detector optical fibers are one of interleaved or inter-woven with the emitter optical fibers.

11. The system of claim 1, wherein the emitter optical fibers, the detector optical fibers are surrounded, at least in part, by reflective surfaces.

18. The optical anti-tamper system of claim 1, further comprising:

the one or more detectors detecting an increased light level within the chassis responsive to cutting the light emitting layer and the light detecting layer both located within the chassis near a protected component; and

means for generating tamper-event warning signal responsive to the detecting.

19. The optical anti-tamper system of claim 18, further comprising:

means for damaging at least a portion of the component within the chassis responsive to generating the tamper-event warning signal, wherein the damaged portion of the component is made at least one of inoperable and irretrievable.

12. A method of manufacture, the method comprising:

positioning at least one light emitting layer within a chassis, the light emitting layer comprising one or more emitter optical fibers, each emitter optical fiber including a plurality of output ports on a side surface of the emitter optical fiber, the output ports operable to transmit light propagating through the emitter optical fiber outside of the emitter optical fiber;

positioning at least one light detecting layer within the chassis operable to receive light from at least one light emitting layer, the light detecting layer comprising one or more detector optical fibers, each detector optical fiber including a plurality of input ports on a side surface of the detector optical fiber, the input ports operable to receive light for propagation within the detector optical fiber;

positioning at least one opaque layer to prevent light from propagating from the light emitting layers to any one of the light detecting layers; and

connecting an alarm in communication with one or more detectors correlated to the light detecting layer.

13. The method of claim 12, further comprising:

closing the chassis when the at least one light emitting layer, at least one light detecting layer, and the at least one opaque layer are positioned; and

calibrating the one or more detectors for an ambient light level within a closed chassis.

14. A method to detect a tampering event, the method comprising:

breaking an opaque layer, wherein the break is located between a light emitting layer and a light detecting layer within a chassis, the light emitting layer comprising one or more emitter optical fibers, each emitter optical fiber including a plurality of output ports on a side surface of the emitter optical fiber, the output ports operable to transmit light propagating through the emitter optical fiber outside of the emitter optical fiber, and the light detecting layer comprising one or more detector optical fibers, each detector optical fiber including a plurality of input ports on a side surface of the detector optical fiber, the input ports operable to receive light for propagation within the detector optical fiber;

transmitting light through a portion of the light detecting layer responsive to breaking the opaque layer;

detecting an increase in a light level at one or more detectors responsive to the transmitting light; and

generating a tamper-event warning signal responsive to the detecting.

15. The method of claim 14, further comprising:

damaging at least a portion of components within the chassis responsive to generating the tamper-event warning signal, wherein the damaged portion of the components is made at least one of inoperable and irretrievable.

16. The method of claim 14, further comprising:

transmitting the tamper-event warning signal responsive to generating the tamper-event warning signal.

17. The method of claim 14, further comprising:

transmitting the tamper-event warning signal responsive to generating the tamper-event warning signal.